1. Field
The present invention relates to an oscillating circuit and a radio communication apparatus.
2. Description of the Related Art
There is known a method using a VCO (Voltage-Controlled Oscillator) circuit as a local oscillator in a radio communication apparatus. As for a harmonic of an oscillation frequency, there is generally known a push-push VCO which obtains a harmonic frequency by inserting an inductor or a transmission line, which exhibits high impedance at the harmonic frequency, between a midpoint portion of inductors and a power supply in order to obtain a harmonic of an oscillation frequency in an LC resonance type VCO (e.g. see Ren-Chieh Liu, Hong-Yeh Chang, Chi-Hsueh Wang, Huei Wang, “A 63 GHz VCO Using a Standard 0.2 μm CMOS Process,” IEEE International Solid-State Circuits Conference, pp. 446-447, 2004)
In the aforementioned method of the above Non Patent Document, the amplitude of the harmonic signal is however small, or an additional amplifier is required.